Btrfs: recursion free-first pass

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index dd11532..6fbaece 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -50,7 +50,7 @@ static int inc_block_ref(struct ctree_root *root, u64 blocknr)
        return 0;
 }
 
-static int lookup_block_ref(struct ctree_root *root, u64 blocknr, int *refs)
+static int lookup_block_ref(struct ctree_root *root, u64 blocknr, u32 *refs)
 {
        struct ctree_path path;
        int ret;
@@ -415,6 +415,100 @@ struct tree_buffer *alloc_free_block(struct ctree_root *root)
        return buf;
 }
 
+int walk_down_tree(struct ctree_root *root, struct ctree_path *path, int *level)
+{
+       struct tree_buffer *next;
+       struct tree_buffer *cur;
+       u64 blocknr;
+       int ret;
+       u32 refs;
+
+       ret = lookup_block_ref(root, path->nodes[*level]->blocknr, &refs);
+       BUG_ON(ret);
+       if (refs > 1)
+               goto out;
+       while(*level > 0) {
+               cur = path->nodes[*level];
+               if (path->slots[*level] >= cur->node.header.nritems)
+                       break;
+               blocknr = cur->node.blockptrs[path->slots[*level]];
+               ret = lookup_block_ref(root, blocknr, &refs);
+               if (refs != 1 || *level == 1) {
+                       path->slots[*level]++;
+                       ret = free_extent(root, blocknr, 1);
+                       BUG_ON(ret);
+                       continue;
+               }
+               BUG_ON(ret);
+               next = read_tree_block(root, blocknr);
+               if (path->nodes[*level-1]) {
+                       tree_block_release(root, path->nodes[*level-1]);
+               }
+               path->nodes[*level-1] = next;
+               *level = node_level(next->node.header.flags);
+               path->slots[*level] = 0;
+       }
+out:
+       ret = free_extent(root, path->nodes[*level]->blocknr, 1);
+       path->nodes[*level] = NULL;
+       *level += 1;
+       BUG_ON(ret);
+       return 0;
+}
+
+int walk_up_tree(struct ctree_root *root, struct ctree_path *path, int *level)
+{
+       int i;
+       int slot;
+       int ret;
+       for(i = *level; i < MAX_LEVEL - 1 && path->nodes[i]; i++) {
+               slot = path->slots[i];
+               if (slot < path->nodes[i]->node.header.nritems - 1) {
+                       path->slots[i]++;
+                       *level = i;
+                       return 0;
+               } else {
+                       ret = free_extent(root,
+                                         path->nodes[*level]->blocknr, 1);
+                       *level = i + 1;
+                       BUG_ON(ret);
+               }
+       }
+       return 1;
+}
+
+int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
+{
+       int ret;
+       int level;
+       struct ctree_path path;
+       int i;
+       int orig_level;
+
+       init_path(&path);
+
+       level = node_level(snap->node.header.flags);
+       orig_level = level;
+       path.nodes[level] = snap;
+       path.slots[level] = 0;
+       while(1) {
+               ret = walk_down_tree(root, &path, &level);
+               if (ret > 0)
+                       break;
+               ret = walk_up_tree(root, &path, &level);
+               if (ret > 0)
+                       break;
+       }
+       for (i = 0; i < orig_level; i++) {
+               if (path.nodes[i])
+                       tree_block_release(root, path.nodes[i]);
+       }
+
+       return 0;
+}
+
+
+#if 0
 int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
 {
        int ret;
@@ -441,4 +535,4 @@ int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
        BUG_ON(ret);
        return 0;
 }
-
+#endif

diff --git a/fs/btrfs/quick-test.c b/fs/btrfs/quick-test.c
index 6400c71..ccca9b2 100644 (file)
--- a/fs/btrfs/quick-test.c
+++ b/fs/btrfs/quick-test.c
@@ -9,7 +9,7 @@
 /* for testing only */
 int next_key(int i, int max_key) {
        return rand() % max_key;
-       //return i;
+       // return i;
 }
 
 int main(int ac, char **av) {
@@ -44,6 +44,9 @@ int main(int ac, char **av) {
                if (!ret)
                        tree_size++;
                free(buf);
+               if (i == run_size - 5) {
+                       commit_transaction(root, &super);
+               }
 
        }
        close_ctree(root, &super);